Mayor's House Record Missing?

Does anyone know why Boris Johnson's purchase of a new house doesn't appear to be in the Land Registry's database anymore?

The Daily Mail reports:

Land Registry documents show Mr Johnson and Ms Wheeler bought the house jointly on June 12, 2009, and that they have a mortgage for the property in both of their names.

Yet searching the Land Registry website shows that no record exists for that date on the road Boris is reported to live on. Does anyone know what's going on? Have I missed something?